1. Field of the Invention
This invention relates to ovens for the heat treatment of glass articles and, more specifically, to tunnel type ovens for continuous treatment of cathode ray tubes at the same time as gases contained within the tube are evacuated, commonly referred to as "exhaust ovens".
2. Description of the Related Art
One example of an exhaust oven for this purpose is described in U.S. Pat. No. 4,752,268.
The heating and cooling of the shaped glass envelope forming the tube to minimise stresses therein and its evacuation which subjects the walls to substantial external pressure is a critical operation. The demand for larger and flatter cathode ray tubes, particularly for domestic high definition "flat screen" television receivers, has increased the processing problems and the need for ovens giving economical production and minimum damage or wastage of these high value components.
The object of the invention is to provide an exhaust oven for cathode ray tubes which is particularly effective and reliable in operation to provide economical and consistent production.